Sputtering has widely been used for manufacture of recording media such as hard disks and optical disks.
However, a target used in a film deposition step during sputtering is only used at an amount of about 40 to 60% at most of its total mass because of the principles of the film deposition method.
Accordingly, recycling of a used target has been desired. This recycling is achieved, for example, by a wet process in which a metal is separated and recovered for each constituent element after being melted by an acid and the like. As another exemplary method of the recycling, a used target may be subjected to a refinement process of a metal that constitutes the target. However, these methods of recovery entail high cost, and are uneconomical.
In response, Patent Literature 1 suggests a method for efficiently recycling a used target. According to Patent Literature 1, a used alloy target material scrap is recycled without separation and refinement of each metal that is a raw material of the scrap, so that the target is recycled at lower cost.
More specifically, the reclamation suggested in Patent Literature 1 is realized by the following steps (i) to (iv). In step (i), a surface of the used alloy target material scrap is cleaned up. In step (ii), the used alloy target material scrap is melted by heating in an inert atmosphere, and is thereafter solidified by cooling, thereby forming an alloy ingot. In step (iii), a surface layer portion located at the top during formation of the alloy ingot is removed, and then in step (iv), the alloy ingot is pulverized, and the resultant alloy powder is subjected to sintering in an inert atmosphere.